Integrally printed blower speed resistor circuit on evaporator

ABSTRACT

An evaporator for dissipating heat from a heating, ventilation and air conditioning (HVAC) system has a first side plate and a second side plate. The second side plate is spaced apart and parallel to the first side plate. An electronic circuit for controlling the HVAC system is printed on the first side plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a heating, ventilation and airconditioning system (HVAC), and more particularly, to an evaporatorapparatus for dissipating heat from the HVAC system.

2. Description of the Prior Art

An automobile heating, ventilating and air conditioning system (HVAC)generally includes a blower motor. Furthermore, the HVAC systemgenerally includes a control module such as a linear power module, apulse width modulator, or a relay resistor module which providesvariable speed control of the blower motor. A disadvantage of thesecontrol modules is that they generate a significant amount of heat thatmust be dissipated to conserve the life of the module. A common mode ofdissipating heat requires that a heat sink be attached to each powercontrol module, and that the heat sink be inserted into the air flow ofthe HVAC system to cool the electronic components inside each powercontrol module. An example of a heat sink and a control module asspecified is shown in U.S. Pat. No. 5,012,656, issued to Yasuji Tamura.

Placing the heat sink and its respective control module into the airflow of the HVAC can produce objectionable tonal noises.

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention is an evaporator apparatus for dissipating heatfrom a heating, ventilation and air conditioning (HVAC) system. Theapparatus includes an evaporator having a first side plate and a secondside plate spaced apart and parallel to the first side plate. Theinvention is distinguished by an electronic circuit for controlling theHVAC system being printed on the first plate of the evaporator.

The present invention eliminates the need for a separate resistor cardby printing the electronic circuit, i.e., the resistor circuit, on thefirst plate of the evaporator. As a result, the evaporator essentiallyfunctions as an effective heat sink thereby eliminating the need to puta resistive speed controller near a throat area of the diffuser. Thus,the present invention provides an evaporator apparatus which results inreduced tonal noise output.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a partial view of a heating, ventilation, and air conditioningmodule of an automobile;

FIG. 2 is a block diagram of a refrigeration, or cooling, circuit of theautomobile air conditioning system; and

FIG. 3 is a perspective view of an evaporator of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, a heating, ventilation, and airconditioning (HVAC) system is shown generally at 20 in FIG. 1.

HVAC system 20 includes a compressor 22 for compressing a refrigerant,and a condenser 24 for receiving the refrigerant from the compressor 22and condensing the refrigerant. HVAC system 20 also includes anexpansion device 25 for receiving the refrigerant from the condenser 24.The expansion device 25 expands the high pressure liquid refrigerantfrom the condenser 24 into a low pressure liquid and vapor mixturebefore it enters an evaporator 26 (also referred to throughout as anevaporator 26 apparatus) used for evaporating the refrigerant. Moreparticularly, the evaporator 26 apparatus provides the function ofabsorbing heat from the air entering the vehicle passenger compartmentwhich will then be dissipated by the condenser 24. The evaporator 26also has the function of directly absorbing the heat generated duringthe voltage reduction of the speed controller for the blower motor.Referring to FIG. 2, a circuit 28 interconnects the compressor 22 andthe condenser 24 and the expansion device 25 and the evaporator 26 fordirecting the refrigerant there through in a particular direction asshown by the arrows bordering the circuit 28.

As shown in FIG. 3, the evaporator 26 has a first side plate 30 and asecond side plate 32 that is spaced apart and parallel to the first sideplate 30. The evaporator 26 is distinguished by having an electroniccircuit 34, also referred to as a resistor circuit or as the blowermotor control circuit, for controlling the HVAC system 20 printed on thefirst side plate 30. The electronic circuit 34 is directly printed ontothe first side plate 30 such that the evaporator 26 operates as a heatsink for waste heat that is generated as voltage to the blower isreduced to achieve the various desired speeds. Preferably, theelectronic circuit 34 is covered with an epoxy (not shown) to protectthe surface of the electronic circuit 34. However, the electroniccircuit 34 may be covered by other materials suitable for protecting thesurface of the electronic circuit 34. The electronic circuit 34 providesvariable speed control for the blower motor (not shown) of the HVACsystem 20. During operation, the HVAC system 20 generates a substantialamount of heat. The heat is dissipated into the evaporator 26 core.

The evaporator 26 also includes an electrical connector 36 that issupported on the first plate 30 and electrically coupled to theelectronic circuit 34. A pair of spaced header tanks 38 and tubes 40extending between the header tanks 38 are further included with theevaporator 26. The side plates 30, 32 of the evaporator 26 interconnectthe header tanks 38. The evaporator 26 also includes a plurality ofcooling fins 42 that separate the tubes 40 between the header tanks 38.An inlet 44 extends into one of the tanks 38 and an outlet 46 extendsfrom the other tank 38.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims.

1. An evaporator apparatus for dissipating heat from a heating,ventilation and air conditioning (HVAC) system comprising: an evaporatorhaving a first side plate and a second side plate spaced apart andparallel to said first side plate, and an electronic circuit forcontrolling said HVAC system printed on said first side plate.
 2. Anapparatus as set forth in claim 1 including an electrical connectorsupported on said first plate and electrically coupled to saidelectronic circuit.
 3. An apparatus as set forth in claim 2 wherein saidevaporator includes a pair of spaced header tanks and tubes extendingbetween said header tanks and said side plates interconnect said headertanks.
 4. An apparatus as set forth in claim 3 including a plurality ofcooling fins separating said tubes between said header tanks.
 5. Anapparatus as set forth in claim 3 including an inlet into one of saidtanks and an outlet extending from the other of said tanks.
 6. Aheating, ventilation and air conditioning (HVAC) system comprising: acompressor for compressing a refrigerant, a condenser for receiving therefrigerant from said compressor and condensing the refrigerant, anexpansion devise for receiving the condensed refrigerant from saidcondenser, an evaporator for receiving the refrigerant from saidcondenser and evaporating the refrigerant, said evaporator having afirst side plate and a second side plate spaced apart and parallel tosaid first side plate, a circuit interconnecting said compressor andsaid condenser and said expansion device and said evaporator fordirecting the refrigerant therethrough in a direction, and an electroniccircuit for controlling said HVAC system printed on said first sideplate.
 7. An apparatus as set forth in claim 6 including an electricalconnector supported on said first side plate and electrically coupled tosaid electronic circuit.
 8. An apparatus as set forth in claim 7 whereinsaid evaporator includes a pair of spaced header tanks and tubesextending between said tanks and said side plates interconnect saidheader tanks.
 9. An apparatus as set forth in claim 8 including aplurality of cooling fins separating said tubes between said headertanks.
 10. An apparatus as set forth in claim 9 including an inlet intoone of said tanks and an outlet extending from the other of said tanks.